M1008 no start

[SnowPlowed]

Starter is good. Battery is good. Wiring is good. Is it possible that something with GP is keeping the signal from getting to the starter.

 

[87cr250r]

These engines are very good at starting if you have a working glow plug system.

If the starter is spinning the engine you either have bad glow plugs or the injection pump is stuck in shutdown.

Do you see white smoke from the exhaust?

 

[SnowPlowed]

Pulled the starter and bench tested it and it’s fine. Glow plugs work but no signal getting to starter to make it go. Turn the key to start and glow plugs come on but starter does not fire. Could it be the glow plug relay?

 

[Barrman]

I think we need some common terms.

The ignition switch has off, on and start.

The glow plug light should come on when you turn the key to on.

Then you have to hold the key in the start position.

If your starter is not working with the key in the start position. Then you get to check wiring. You can start with the small wire on the starter solenoid since you were just there checking the starter. It should have 24 volts only when someone holds the key in the start position.

If it does have 24 volts then your starter has issues. Even though you tested it.

If it doesn’t have 24 volts. Then follow the wire all the way across the engine and firewall to the plug at the back of the fuse panel. You will probably find nothing wrong until you get under the dash above the throttle pedal. The starter relay is located under where the radio would be in a civilian truck on a little plate.

It has 4 wires.
24 volts always hot.
Ground.
The wire to the starter solenoid
12 volt positive when the key is in start position.

If all of those wire do as described then the relay is bad. If the 12 volt start signal isn’t happening then it could be your ignition switch or the position of the ignition switch could have shifted causing it n to to work.

 

[SnowPlowed]

I think we need some common terms.

The ignition switch has off, on and start.

The glow plug light should come on when you turn the key to on.

Then you have to hold the key in the start position.

If your starter is not working with the key in the start position. Then you get to check wiring. You can start with the small wire on the starter solenoid since you were just there checking the starter. It should have 24 volts only when someone holds the key in the start position.

If it does have 24 volts then your starter has issues. Even though you tested it.

If it doesn’t have 24 volts. Then follow the wire all the way across the engine and firewall to the plug at the back of the fuse panel. You will probably find nothing wrong until you get under the dash above the throttle pedal. The starter relay is located under where the radio would be in a civilian truck on a little plate.

It has 4 wires.
24 volts always hot.
Ground.
The wire to the starter solenoid
12 volt positive when the key is in start position.

If all of those wire do as described then the relay is bad. If the 12 volt start signal isn’t happening then it could be your ignition switch or the position of the ignition switch could have shifted causing it n to to work.

Thanks for that. Yeah it is a no start when the key is in the start position. Starter doesn’t spin or click or anything. I’ll start tracing wires and testing with the multimeter. Thanks for the help. I appreciate the specific details about the starter relay etc.

 

[SnowPlowed]

Well no visible signs in the ignition switch but now I’m remembering it did stick in the start position when it was really cold about a month ago. I bet that’s the culprit. I am replacing that and the starter relay and hoping I’m back up and running.

 

[spankybear]

The start relay under the dash maybe bad... It's on a plate above the ICE connector.

 

[Barrman]

Physically verify front battery voltage. One of my CUCV’s last week did nothing when I moved the key to start. I jumped in another one and drove away. I finally had a chance to check the other truck and found 7.5 volts at the front battery. 6 years old. I charged it up and the vehicle has started perfectly ever since.

Always start like the TM says with battery voltage and load testing.

 

[Buck69]

Is there not a safety neutral switch in your truck? Did you try it with transmission shifted into neutral?

 

[SnowPlowed]

I'm back up and running strong. Ok, so here is what I did. I replaced the ignition switch on the steering column, the glow plug relay (making some funny noises) on the firewall, I did the starter relay modification (getting some bad voltage readings at the relay), pulled the starter once again and had it rebuilt (turns out the starter was totally fried; possibly occurring post original test), I rewired and beefed up all battery connections and starter connections (some of these where fraying). It was quite the process and I am not sure if anyone of these things was the lone culprit; rather, I think I was having some cumulative issues that made it hard to diagnose, including one of the trickle chargers I have installed on the front battery turned out to be bad so the front battery finally died because the truck wasn't running for so long and it wasn't charging when I had it plugged in. Safe to say I learned quite a few things. . .

Thanks for everyone's help and suggestions.